In general, various reaction gases employed for forming films on wafers or etching wafers in a semiconductor manufacturing process contain oxidation components, phosphide components, toxic components, etc. Therefore, if such a reaction gas (hereinafter, to be referred to as “waste gas”) is discharged after use to the atmosphere as it is, it is not only harmful to human body but also causes environmental contamination. Consequently, there is provided a scrubber in a semiconductor installation so as to discharge such a waste gas after removing oxidation components, phosphide components, toxic components, etc.
A semiconductor waste gas processing scrubber for removing a waste gas during a semiconductor fabrication process is classified into three types: i) an indirect burning and wet type scrubber, which burns a waste gas and then filters the gas once again using water, wherein the scrubber is also called as a “heat wet scrubber,” ii) a wet type scrubber, which captures a waste gas using water and then purifies the water, wherein the scrubber is also called as a “wet scrubber,” and iii) a direct burning and wet type scrubber, which burns a waste gas using flame of high temperature and then captures the gas using water, wherein the scrubber is also called as a “burn wet scrubber.”
Herein, the semiconductor waste gases are mainly silicon-containing gases, which produce a large quantity of particles when processed by a heat wet scrubber or a bun wet scrubber. An example of a chemical formula may be indicated as follows:SiH4(gas)+2O2→SiO2 (particles)+2H2O
Like this, if such a semiconductor waste gas is burnt, a large quantity of particles is produced. Therefore, it is possible to substantially reduce the density of harmful components in the semiconductor waste gas if the particles are filtered and captured using water.
However, the conventional semiconductor waste gas processing scrubbers as mentioned above have various problems as follows.
First, a conventional scrubber has a problem in that a burner employed in such a scrubber is not superior in efficiency for burning a semiconductor waste gas and thus cannot completely burn the semiconductor waste gas. That is, there is a problem in that the burner is supplied with fuel and oxygen as well as a semiconductor waste gas, wherein because the waste gas, the fuel and the oxygen are supplied in such a manner as to flow parallel to each other, they are not rapidly mixed with each other, whereby the burner is poor in efficiency for burning the semiconductor waste gas.
Second, the particles, which have been generated after burning the semiconductor waste gas, gradually thickly deposit on the inner wall of a burning chamber due to attractive force and frictional force, and solidified as time goes. Therefore, there is a problem of inconvenience in that the entire inner wall of the burning chamber should be manually cleaned after a given time period has passed. In general, the inner wall of such a burning chamber should be cleaned, usually once every three or four days.
Third, in order to clean the burning chamber as mentioned above, it is necessary to completely separate the burning chamber from a scrubber case. However, in a conventional semiconductor waste gas processing scrubber, the separation and connection of such a burning chamber require very long time because the burning chamber is fixed by a number of bolts and nuts.
Fourth, a wet scrubber or a burn wet scrubber as mentioned above may include a wet tower for injecting a predetermined quantity of water. Apart from spraying water, such a wet tower is typically provided with a plurality of filters so as to filter and remove particles. However, such a scrubber is not effective in that such a wet type tower should be continuously used without changing the assembled condition, even if it is once assembled without considering various process conditions and installation status. In addition, with such a conventional wet tower, it may be occasionally sufficient to clean a specific area when cleaning the inside of the wet tower. In such a case, however, because it is also required to entirely separate the wet tower, it takes very long time to clean the specific area.
Fifth, a wet scrubber or a burn wet scrubber as mentioned above may include a water reservoir tank in which a predetermined quantity of water is contained. Such a water reservoir tank serves to cause particles, which are formed from a semiconductor waste gas as being burnt by flame from a burner, to be captured in water. Of course, such particles and water may be discharged to the outside every predetermined time interval, and fresh water may be supplied to the water reservoir tank. However, the particles captured in the water in the water reservoir tank as described above settle and accumulate on the bottom of the water reservoir tank by weight as time passes. As they are more thickly accumulate due to their weight as time passes, the particles are consequently adhered to the bottom of the water reservoir tank due to the self-weight thereof, whereby the particles are not discharged to the outside even if the water is discharged. Accordingly, the prior art has a problem in that it is necessary to separate and clean the water reservoir tank every predetermined time period, which is significantly labor intensive and time consuming.